Real-Time Microradiography of Pearls: A Comparison Between Detectors
Compares the image quality provided by real-time microradiographic imaging (RTX) units fitted with two different detectors: an image intensifier (II) and a flat panel detector (FPD).
Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards
Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.
Dyed Quartzite Imitation of Ruby-in-Zoisite
Beads appearing to be ruby-in-zoisite are revealed to be dyed quartzite.
Observations on HPHT-Grown Synthetic Diamonds: A Review
Summarizes statistical data and distinctive features of several thousand gem-quality HPHT synthetic diamonds examined by GIA from 2007 through 2016.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study
Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.
X-ray Computed Microtomography: Distinguishing Natural Pearls from Beaded and Non-Beaded Cultured Pearls
The distinction of natural from cultured pearls traditionally has been based on X-radiography.
True Colors of “Dalmatian Jasper”
Discusses the mineralogical composition and provenance of this spotted decorative gemstone.
Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany
Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s through the 1970s.
Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia
Compares PL spectroscopy data of 48 emerald samples from three countries to evaluate the usefulness of the technique in geographic origin determination.
The Latest on Synthetic Diamonds
Dr. James Shigley, GIA distinguished research fellow, is one of the foremost experts in diamonds and their identification. In this presentation recorded at the 2017 JCK Las Vegas show, he shares the latest developments about HPHT and CVD synthetic diamond